【前端每日一题】day5

JS 实现继承的几种方式

在JavaScript中，实现继承的几种方式包括原型链继承、构造函数继承、组合继承、原型式继承、寄生式继承和组合式继承。

原型链继承：

function Parent() {
    this.name = 'Parent';
}
Parent.prototype.sayHello = function() {
    console.log('Hello, I am ' + this.name);
};

function Child() {}
Child.prototype = new Parent();

var child = new Child();
child.sayHello(); // 输出: Hello, I am Parent

构造函数继承：

function Parent() {
    this.name = 'Parent';
}

function Child() {
    Parent.call(this);
}

var child = new Child();
console.log(child.name); // 输出: Parent

组合继承：

function Parent() {
    this.name = 'Parent';
}
Parent.prototype.sayHello = function() {
    console.log('Hello, I am ' + this.name);
};

function Child() {
    Parent.call(this);
}
Child.prototype = new Parent();
Child.prototype.constructor = Child;

var child = new Child();
child.sayHello(); // 输出: Hello, I am Parent

原型式继承：

function object(o) {
    function F() {}
    F.prototype = o;
    return new F();
}

var parent = {
    name: 'Parent',
    sayHello: function() {
        console.log('Hello, I am ' + this.name);
    }
};

var child = object(parent);
child.sayHello(); // 输出: Hello, I am Parent

寄生式继承：

function createAnother(original) {
    var clone = Object.create(original);
    clone.sayHello = function() {
        console.log('Hello, I am ' + this.name);
    };
    return clone;
}

var parent = {
    name: 'Parent'
};

var child = createAnother(parent);
child.sayHello(); // 输出: Hello, I am Parent

组合式继承：

function Parent(name) {
    this.name = name;
}
Parent.prototype.sayHello = function() {
    console.log('Hello, I am ' + this.name);
};

function Child(name) {
    Parent.call(this, name);
}
Child.prototype = Object.create(Parent.prototype);
Child.prototype.constructor = Child;

var child = new Child('Child');
child.sayHello(); // 输出: Hello, I am Child